The invention relates to a filter element which will exhibit a desired degree of rigidity and yet is sufficiently flexible that it can be bent in one direction to a curved configuration. Such a filter element can be used to filter the fresh air supply in a motor vehicle. The filter element typically is composed of a particle filter, and if desired, may also include a supplementary activated carbon filter. It is advantageous to configure the filter element in such a way that it exhibits a high rigidity, so that it will seal reliably in the receptacle for the filter element, and so that raw or unfiltered air cannot pass around the filter to the clean air side of the filter. On the other hand there is a requirement to construct the filter element to be flexible, especially when the installation conditions are restricted, so that the filter can be assembled in its desired location in a simple manner. For this purpose various solutions are known.
It is the object of the invention to provide an improved filter element.
It is also an object of the invention to provide a filter element which is sufficiently rigid that it will seal properly in its receptacle so that raw or unfiltered air cannot bypass the filter.
An additional object of the invention is to provide a filter which is sufficiently flexible that it can be easily installed even in a restricted location.
These and other objects are achieved in accordance with the present invention by providing a filter element comprising a pleated filter medium provided on its periphery with a gasket element, further comprising at least one adhesive track or reinforcing member extending across one side of the filter medium transversely to the pleats such that the filter element is reinforced but can still be bent to a curved configuration in one direction.
In accordance with a further aspect of the invention, the objects of the invention are achieved by providing a filter apparatus comprising a housing, a filter element seated in said housing, a raw air inlet on one side of the filter element, a clean air outlet on the other side of the filter element, and a passageway for introducing the filter element into the housing, wherein the filter element is comprised of a pleated filter medium having a gasket element on its periphery, and wherein on one side of the filter medium at least one adhesive track or reinforcing member is arranged transversely to the pleats such that the filter element can be bent to a curved configuration in one direction.
The substantial advantage of the filter element according to the invention is that the pleated filter non-woven web or filter paper is provided on one side with one or more adhesive tracks or beads or other stabilizing elements, so that this side of the filter element has a high rigidity, while on the opposite side the filter element is flexible and it is possible to bend the filter element during the installation phase.
In accordance with one embodiment of the invention, adhesive tracks or reinforcing members are provided on both sides of the filter element. The difference between the reinforcing members or the adhesive tracks on the first side relative to the adhesive track on the opposite side is that the elasticity of the adhesive of the adhesive tracks is different, so that even in this case on one side a high degree of rigidity is assured and on the other side a high resilience or elasticity.
An alternative embodiment envisions adjusting the strength of the adhesive track in accordance with the required elasticity or stability of the filter.
One advantageous use of the filter element is for filtering air for the passenger compartment of a motor vehicle. For this purpose the filter element is inserted into a receptacle above a passageway. While in this receptacle, raw air flows through the filter element and is cleaned, and the clean air is guided by the shaft or duct to the passenger compartment of the motor vehicle.
It is well known that the space available for installing devices in motor vehicles is very limited. For this reason, the filter element is guided to its position through a curved passageway. In order to successfully pass through this curved passageway, the filter element must adapt to the curvature. It is therefore necessary that the filter element be deformable. On the other hand, a high degree of rigidity must be assured, so that the filter element can be pushed into position through the installation shaft or duct and so that it will seal properly when installed in place in its receptacle.
These and further features of preferred embodiments of the invention are found not only in the claims, but also in the description and the drawings, and the respective features can be realized individually or jointly in the form of subcombinations in embodiments of the invention and in other fields of use, and may represent advantageous and independently protectible embodiments, for which protection is also claimed.